Slavery. Adorable slavery.
I got the five chims as fast as possible (not that hard on a second playthrough) and had atleast four of them make yeast. First just regular ones, but later on with Price Up L. The regular ones sold for 116 cole, the better ones for 168. You can get even more if they're a high rank (mine were B, I think). Quality doesn't seem to matter. Anyway, an inexperienced chim needs two days to make one, an experienced one only one. So with 4-5 chims working, you'll eventually make 500-1000 cole a day. It makes it quite easy to make 250,000-300,000 cole in the final year alone. Just make sure you've got plenty of pies (but them at Ceci's, 10 for 700 cole, stores restock on days ending on 1 and 2) and space in your container.
Once you've got the chims working for you, you'll never need to worry about money again. Need a particular alchemy item for a big recipe? Just register it and buy it. The chims will make it back in a day, two at most. It's much more efficient than having them make stuff, which can easily take a week per item. The only other job you may want to give them is gathering. It's a great way to duplicate rare and high quality ingredients. For instance, it takes a chim only 7 or 8 days to get a dragon horn. Totori needs 8 days (or was it 9?) to even find a dragon!
Sell your leftover ingredients and other stuff (you can't take it with you to the next playthrough anyway) in the final week for another 60,000-80,000 cole.